The present invention relates to a compact, mechanically operated switch which can selectively control one or more of a plurality of different switching functions and, more particularly, to an improved switch suitable for use as a hook switch in a telephone set.
One recent trend in the telephone set industry is the development of various unique functions for user's convenience in addition to improvements in basic transmitting and receiving functions. For example, telephone sets are known which enable transmitting a call without lifting a handset. Such added function is conventionally implemented purely electrically as by using a separately provided control box having relays. When a specific pushbutton in the telephone set is depressed, the control relays operate to establish a network circuit as well as a loudspeaker receiving circuit, thus enabling transmitting a call without lifting the handset.
However, there are several problems in that such telephone sets equipped with separate control relays are very costly to the extent of preventing their widespread use especially by ordinary households, that there are space constraints in the telephone set for accommodating a separate control box, and that provision of such separate control circuits is essential because of higher voltages and currents used in the telephone set.